<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body></body>
<script>
'use strict';

function createIframe(iframe) {
  return new Promise(resolve => {
    iframe.src = '';
    iframe.onload = () => {
      resolve(iframe.contentWindow.navigator.usb);
    };
    document.body.appendChild(iframe);
  });
}

promise_test(async(t) => {
  let iframe = document.createElement('iframe');
  let iframeUsbObject = await createIframe(iframe);
  let devices = await iframeUsbObject.getDevices();
  assert_equals(devices.length, 0);
  document.body.removeChild(iframe);
  // Set iframe to null to ensure that the GC cleans up as much as possible.
  iframe = null;
  GCController.collect();
  return iframeUsbObject.getDevices()
      .catch(err => assert_equals(err.name, 'NotSupportedError'));
  }, 'detaching from iframe invalidates reference to the iframe USB object');
</script>
